CVE-2026-101335 wpmudev CVE debrief

Who should care

Defenders responsible for WordPress installations using the Forminator Forms plugin should assess exposure and prioritize patching or mitigation efforts, focusing on verifying Forminator Forms versions, evaluating potential impact, and coordinating with relevant stakeholders to ensure timely remediation and minimize potential risks.

Why it matters

CVE-2026-101335 allows unauthenticated attackers to execute arbitrary WordPress shortcodes, potentially leading to content injection, information disclosure, and unauthorized changes. Defenders should verify Forminator Forms versions, assess exposure, and apply patches or mitigations.

• Arbitrary content injection through shortcode execution
• Information disclosure through shortcode execution
• Potential for unauthorized changes to site content
• Verification of shortcode exposure and impact required

Technical summary

The Forminator Forms – Contact Form, Payment Form & Custom Form Builder plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions up to, and including, 1.58.1. This is due to the forminator_replace_quiz_form_data() helper invoking do_shortcode() on the fully expanded notification body once the {quiz_result} merge tag has been substituted, while the earlier-substituted {user_agent} and {refer_url} merge tags carry unauthenticated attacker-controlled bytes through sanitize_text_field()/esc_html(), neither of which strip the '[' and ']' shortcode delimiters.

Defensive priority

Defenders should prioritize verifying the versions of Forminator Forms in use, assessing exposure, and applying patches or mitigations as needed.

Recommended defensive actions

• Verify the version of Forminator Forms in use and assess exposure
• Apply patches or mitigations as needed
• Monitor for suspicious activity related to quiz submissions and shortcode execution
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is due to the forminator_replace_quiz_form_data() helper invoking do_shortcode() on the fully expanded notification body. The earlier-substituted {user_agent} and {refer_url} merge tags carry unauthenticated attacker-controlled bytes through sanitize_text_field()/esc_html(), which do not strip the '[' and ']' shortcode delimiters.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.